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themagicone
join:2003-08-13
Osseo, MN

themagicone

Member

400 amp service and general electric question

Just curious to see if anyone would have a ball park estimate on what it cost to install a 400amp service for a house. Reason I ask is I don't think 200amps is going to be enough to cover all my circuits I need even though I don't think I'll ever use over 100amps at a given time. So far I have:
In the kitchen alone:
1 x 30amp 240v for the oven
2 x 15amp for outlets
1 x 15 amp for fridge
1 x 20 amp for warming drawer
1 x 15 amp for dishwasher/disposal
1 x 15 amp for range vent
1 x 15 amp for lighting
___________________
140 amps of breakers just for kitchen!

Master bath:
1 x 15 amp for outlets
1 x 15 amp for lighting/fans
1 x 20 amp for whirlpool
____________________
50 amps more

Still have 4 bedrooms, 3 more baths, 2 living rooms, garage, outside power, hvac system, etc.

Am I over doing it or? Any opinions, thoughts? Thanks
ImpetusEra
Premium Member
join:2004-05-19
00000

ImpetusEra

Premium Member

The size of the breaker is only protecting the wire from carrying more current than it can handle. You can have 1000 amps worth of breakers in a 100 amp panel yet you'll never be able to use more than 100amps because the main breaker will trip. A 150amp or 200amp service would likely be fine.

shdesigns
Powered By Infinite Improbabilty Drive
Premium Member
join:2000-12-01
Stone Mountain, GA
(Software) pfSense
ARRIS SB6121

shdesigns to themagicone

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to themagicone
200 amp is Two 200A phases. All 120V circuits use one of the two. So you could have 400A of 120V load.

220V loads use both phases. So, count as 2 laods (has 2 breakers).

Mine is a 150A service and have probably close to 300A in breakers. Normally, you may see more amps in breakers than the service provides. It assumes most are not fully loaded.

You need to look at the loads, not the breakers. A fridge will probably be 8A not 15. The 220V loads are usually the big ones.

I would also do 20A for most outlet circuits unless it is a dedicated outlet.

cdru
Go Colts
MVM
join:2003-05-14
Fort Wayne, IN

cdru

MVM

said by shdesigns:

200 amp is Two 200A phases.
...
220V loads use both phases.
Those are legs of a single split-phase supply line, not separate phase.

shdesigns
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Stone Mountain, GA
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shdesigns

Premium Member

said by cdru:

Those are legs of a single split-phase supply line, not separate phase.
Two phases at 180 degrees. Split phase yes, but both are called phases.

Killa200
Premium Member
join:2005-12-02
TN

Killa200 to shdesigns

Premium Member

to shdesigns
Just as an example of what shdesigns is saying to the OP:

Our home has 400A 240V split phase service. Currently right now between both panels, we're looking at a total of 46 of 60 slots used, with a total single pole usage of 1035Amps (if everything was on and maxed... very doubtful to ever happen). That service has a single pole max of 800Amp.

Nothing bad has happen yet, except a huge electric bill from time to time, lol.
themagicone
join:2003-08-13
Osseo, MN

themagicone

Member

Ah that makes sense. I've done electric, just never sized a panel or service. I thought you were only allowed a total of 200 amps in breakers on a 200amp box. That put's my mind at ease considering how much a electric bill could be at 400 amps.

nunya
LXI 483
MVM
join:2000-12-23
O Fallon, MO
·Charter

1 edit

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nunya to themagicone

MVM

to themagicone
Residential service is typically a center tapped single phase. Thus the term "single phase". The maximum you are going to draw, pole to pole, is 200 Amps.
2 phase service is EXTREMELY rare. I've only installed 2 over the years. One was for an apartment building in a mostly commercial location, and the other a cell site.

The cumulative sum of the branch circuit breaker ratings means absolutely nothing.
Panel size is determined by a load calculation. There are to methods - standard and optional. These can be done by an electrician, engineer, and sometimes architect.

Often the panel size is dictated by the muni or poco. In some instances, a 100A panel may be sufficient, but the poco may only sell 200A, or the smallest service the muni allows is 200A.

Given the very light loads you have listed, I'd say 200A is probably more than enough. Unless you have electric heat (which I doubt seriously in MN), I don't think you would need to waste your money on a load calculation, unless this is a house yet to be built. In which case a load calculation is a must.

John Galt6
Forward, March
Premium Member
join:2004-09-30
Happy Camp

John Galt6

Premium Member

said by nunya:

Given the very light loads you have listed, I'd say 200A is probably more than enough. Unless you have electric heat (which I doubt seriously in MN), I don't think you would need to waste your money on a load calculation, unless this is a house yet to be built. In which case a load calculation is a must.
What he said...

You might need more CB spaces than a single panel can provide. In that case you install subpanels.

Is this for a new build or remodel?

Also, how many square feet in either case?

whizkid3
MVM
join:2002-02-21
Queens, NY

whizkid3 to themagicone

MVM

to themagicone
nunya has it right on the money (again).

To begin with, as others have said, you should be looking at 240V, 200A service. That's 48kVA! Probably just about the transformer rating for 2-3 houses, anyway. If you don't think you'll use over 100A, then you probably don't even need a 200A service.

The second point is that one never simply adds up the breaker ratings (whether it is done right or wrong, as you have done by not considering the 240V). Demand load calculations are performed. And they have to be performed properly. There are great examples in the back of the NEC - check them out.

If you can't do the calculations (which use volt-amps & watts - not amps), then have an electrical, electrical engineer or residential architect do them.

Splitpair
Premium Member
join:2000-07-29
Cow Towne

Splitpair to shdesigns

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to shdesigns
said by shdesigns:

Two phases at 180 degrees. Split phase yes, but both are called phases.
Nope they are hot legs and are considered single phase.

Wayne

i1me2ao
Premium Member
join:2001-03-03
TEXAS

i1me2ao to nunya

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to nunya
who needs more than 200 amp residential panel for electric heat? just out of curiosity?

shdesigns
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shdesigns to Splitpair

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to Splitpair
said by Splitpair:
said by shdesigns:

Two phases at 180 degrees. Split phase yes, but both are called phases.
Nope they are hot legs and are considered single phase.

Wayne
Semantics, shemantics. Always referred to as 2-phase on my power systems classes "sometimes called split phase".

Glad i no longer have to calc all that phase and balance currents, dops, efficiency on 2, 3, 4 and 6-phase systems. Boring stuff.

jchambers28
Premium Member
join:2007-05-12
Peculiar, MO

2 edits

jchambers28 to Splitpair

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to Splitpair
the differences between single phase and 3 phase is the number of hot wires entering the panel. single phase uses 2 hot wires. 3 phase uses 3 hot wires or more.

fcisler
Premium Member
join:2004-06-14
Riverhead, NY

1 recommendation

fcisler to shdesigns

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to shdesigns
said by shdesigns:

Semantics, shemantics. Always referred to as 2-phase on my power systems classes "sometimes called split phase".
Then demand a refund from those classes as they are wrong. Single (or split) phase is NOT the same thing as two (or poly) phase.
patcat88
join:2002-04-05
Jamaica, NY

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patcat88 to i1me2ao

Member

to i1me2ao
said by i1me2ao:

who needs more than 200 amp residential panel for electric heat? just out of curiosity?
If you have a mansion. Electric pool heaters. Wave generator or swimming machines. Multiple kitchens. Elevator. 3 phase air conditioner. Instant electric water heaters. Landscape lights. Water fountains. Stadium field lighting for your tennis, golf and polo courts. Hot tubs that fit 30 people. Home theater that puts the multiplex to shame. Tanning beds. Maids doing laundry in laundry rooms with industrial washers. The horse barn. etc

Excluding a mansion, a 400 amp service is good if you plan to have multiple families, legally or illegally in the home, or if you want to charge your EV car/cars one day, or big on instant water heaters. Your power will be quite expensive if you ever get more than 400 amps flowing for more than a few minutes. A floored 200 amp service will pump ((400*120)/1000)*.20=$9.60 per hour assuming $.20 per kwh (I think an average post-tax power rate in the USA).

A floored 400 amp service will pump
((800*120)/1000)*.20 = $19.20 per hour. Is that really something you can afford?

High amp services really only make sense if you think of what insane power usage for only a few minutes thing your going to have. Instant water heaters are a big one today. Electric cars will be in the future. If you want to weld ships or construction equipment at home, operate a kilm, or use anything commercial, insane services would make sense.

edit: spelling

i1me2ao
Premium Member
join:2001-03-03
TEXAS

i1me2ao

Premium Member

thanks, basically al gore..

whizkid3
MVM
join:2002-02-21
Queens, NY

2 edits

whizkid3 to fcisler

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to fcisler
said by fcisler:

said by shdesigns:

Semantics, shemantics. Always referred to as 2-phase on my power systems classes "sometimes called split phase".
Then demand a refund from those classes as they are wrong. Single (or split) phase is NOT the same thing as two (or poly) phase.
Agreed. If you had an instructor that called 240V single-phase service 'two-phase', in a power course no-less, then they probably were not that good of an instructor. Its an elementary mistake in fundamentals.

Jahntassa
What, I can have feathers
Premium Member
join:2006-04-14
Conway, SC

Jahntassa to i1me2ao

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to i1me2ao
said by i1me2ao:

who needs more than 200 amp residential panel for electric heat? just out of curiosity?
I have 400a service, but half of that is for around 100 computers.

telcotech
IBEW 2222 Boston, MA
Premium Member
join:2004-09-02
united state

telcotech

Premium Member

You've got 100 computers in a residence??
Bobcat79
Premium Member
join:2001-02-04

1 recommendation

Bobcat79 to patcat88

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to patcat88
You left out the grow lights.
themagicone
join:2003-08-13
Osseo, MN

1 edit

themagicone

Member

Quiet.... you weren't suppose to know that. How else am I to pay for the house???? May be I should take some cues from This Old House and just tap onto the 48kv 3 phase hanging on the huge pole behind my house?
tomdlgns
Premium Member
join:2003-03-21

tomdlgns to themagicone

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someone correct me if i am wrong, but we just upgraded from 200 amp to 400 amp service at our business (i understand businesses may be treated differently) but i was told that if we can prove that we need 400 amp, our electrical company (ComEd) does not charge us to give us the 400 amp service, but as i stated above, we need to show proof that we need the extra 200 amps.

we were able to do this by listing out what we plan on doing in the future and they had no problem giving us the 400 amp service.

not sure if the same applies for residential. we have an aerial run from the pole to our building, there might be some costs associated if wire is underground (assuming more wires or new wires are part of the process)
tomdlgns

tomdlgns to themagicone

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to themagicone
said by themagicone:

Reason I ask is I don't think 200amps is going to be enough to cover all my circuits I need even though I don't think I'll ever use over 100amps at a given time. So far I have:

good point, if you are not using everything at once, you should be ok, but something that i would like to point out is what happens during a power outage/spike when everything drops/shuts off and then kicks back on all at once.

again, just like you said, if everything isn't being used at once, you should be ok, but some appliances can still draw their max amps when getting a power feed to them coming online from a power outage.

Jahntassa
What, I can have feathers
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join:2006-04-14
Conway, SC

Jahntassa to telcotech

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to telcotech
said by telcotech:

You've got 100 computers in a residence??
Yup, but they're for work.

As far as costs / permits. I think I came in around $3~$4k for the service upgrade, second panel, sub panel, and outlet wiring. I don't know if the utility charged the people doing the work for a new meter / mains run, but I paid for the meter box.

The county called me when they were running the permits to ask why I needed the power, and I said for business computers, and they said okay, nothing else.

nunya
LXI 483
MVM
join:2000-12-23
O Fallon, MO
·Charter

nunya to tomdlgns

MVM

to tomdlgns

good point, if you are not using everything at once, you should be ok, but something that i would like to point out is what happens during a power outage/spike when everything drops/shuts off and then kicks back on all at once.

again, just like you said, if everything isn't being used at once, you should be ok, but some appliances can still draw their max amps when getting a power feed to them coming online from a power outage.


Your theory doesn't hold water. We've already explained this above.
tomdlgns
Premium Member
join:2003-03-21

tomdlgns

Premium Member

that's fine.

we have a battery charger that spikes at 30 or 40 amps when we come back from a power outage.

as i stated above, business setups will be somewhat different than a residential setup.

nunya
LXI 483
MVM
join:2000-12-23
O Fallon, MO
·Charter

nunya to themagicone

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The systems are designed to handle brief periods of overcurrent while high demand items start up. A 200A breaker doesn't trip the instant 200A is reached. Breakers trip on an inverse time delay. A hard short that might be 10,000 Amps will trip instantaneously, whereas a 201 Amp load might take 3 hours to trip.

ctceo
Premium Member
join:2001-04-26
South Bend, IN

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ctceo to themagicone

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to themagicone
Wow, 400 amp. I don't mean to jump off topic, but I remember living in the old converted barn house in the county where 1 microwave and 1 TV couldn't be used at the same time. 60 Amp service, man those were the days, lol. We even had to turn off the TV sometimes while the furnace (something akin to a miniature locomotive engine) was running. This thing was huge.

Edit to add:
After thinking about it I think there was 2 outlets downstairs, 2 in the kitchen, 2 upstairs, and the breaker box was no bigger than say 9x9 inches square with 2 big fuses and 2 switches.

telcotech
IBEW 2222 Boston, MA
Premium Member
join:2004-09-02
united state

telcotech to Jahntassa

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to Jahntassa
Pretty interesting. I hope you're capturing the heat to offset your heat energy costs. Did the utility want to hit you with any premiums / penalties or charge you a commercial rate for power?

I know a fellow in Clinton, MA that ran the number #1 BBS (remember BBSs?) in the US from his home. At its peak, there were over 100 telephone lines that were installed there. People were wondering if he was "making book" there! He told the TelCo what he was doing and they - like your electric company - just said "OK". That was it.